Variable gearing for bicycles or the like.



PATENTED AUG. 11, 1903."

, F. MITGHELL. VARIABLE GEARING FOR'BIGYGLES OR THE LIKE.

APPLIOATION FEED AUG. 2, 1902. N0 MODEL. 3 SHEETS SHEET 1.

No. 736,129. PAT-BNTED AUG. 11, 1903.

- 'P; MITCHELL. VARIABLE GEARING F0 R BICYGLES OR THE LIKE.

APPIIIGATION IILBD AUG. 2, 1902. N0 MODEL. 3 SHEBTSSHEET 2.

PATENTED AUG. 11, 1903;

F. MITCHELL. VARIABLE GEARING FOR BIGYOLES OR THE LIKE.

APPLIOATION TILED AUG. 2, 1902.

a SHEETS-SHEET a.

no aobnL.

Patented August 11, 19.03.

'ATENT OFFICE.

FRANK MITCHELL, OF LONDON, ENGLAND. I

VARIABLE GEARINe FOR BICYCLES OR THE LIKE.

SPECIFICATION forming part of Letters Patent No. 736,129, dated August11, 1903. a

' Applioationfiled August 2, 1902.

clear, and exact description.

My invention relates to an improved means by which the gearing or therelation between the speed of the pedals or driving power and I that ofthe cycle or other vehicle may be vadirection of the arrow 00.

ried by the rider while the machineis in motion, so as to enable him tomore easily contend with the varying resistances experienced whileriding. i v I will describe my invention by the aid of the accompanyingdrawings, in which- Figure 1 is a face view of the gearing applied to anordinary safety-bicycle, showing one of the clutches in section. Fig. 2is a section on the line 2.2 of Fig. 1 looking in the Fig. 3 is a viewof part of the apparatus, showing how certain parts may be moved inrelation to one another whereby the gearing is altered. Fig.

4 is a perspective viewshowin g how thegearing is attached to the bottombracket of a bicycle. 'Figs..5, 6, and 7 are views showing modificationsin the method of connecting the driving and the driven parts. Fig. 8shows a modified form .of one of the clutches. Fig. 9 shows a modifiedform of apparatus for rotating the screw shown in Fig. 3 and therebyaltering'the gear ratio.

The bottom bracket or and the crank-spin dle b may be of any ordinaryconstruction.

The spindle b is driven by cranks '0, (only one of which is shown',)which latter are connected to the spindle b in any well-known manner.The crank which is not shown has no connection with the gearing hereindescribed, and throughout the remainder of the; specification I shallonly refer to that crank which is shown.

To the bottom bracket a is rigidly connected a plate-CZ by means of theclips CZ (Z and curved guides (Z and d The fixed plate 01 is providedwith a slidingportion d working in suitable guides in said plate d. Thesliding portion d? is provided with a ball-bearing d upon which runs theclutch-plate 6, pro- Serial No. 113,089. (No model.)

vided with a groove 8 for the driving-clutches, to be hereinafterdescribed. The chain-teeth e are carried by the clutch-plate earound theoutside of the groove 6. It will thus be understood that the slidingportion LP, the clutch-plate e, and the parts carried by this latter maybe moved in relation to the fixed plate 01 and spindle b.

To the crank c is fixed a disk f, which consequently rotates at the samespeed therewith. It is obvious that a number of separate arms may beemployed instead of a disk. This diskf or other rotating part or partsis or are connected in any suitable manner to a number of clutches g,which drive the clutchi plate 6 with its groove 6' and chain-teeth e InFigs. 1, 2, 5, 6, and 7 the clutches g are shown working in the groovee. In Figs. 1 and 2 the diskfis connected to the clutches g by pivotedrods g, which act in tension, the parts rotating in the direction shownby the arrows. In Fig. 5 the diskfis connected to the clutches g bypivoted rods g, which act in compression. In Figs. 6 and 7 the diskf isprovided with rods or leversf. In Fig. 6 the rods or levers f have slotsf working over pins 9 attached to the clutches g. In Fig. 7 the rods orleversf slide between noses 9 forming part of the clutches g, and areheld between said noses g by means of lugs 9 carried by the clutches g.In all these the clutches g are likewise rotated and drive theclutch-plate e and chain-teeth e It will be understood that when theclutchplate (2 and diskf are concentric all the clutches 9 come intoaction and the chainteeth e are driven at the same speed as the crank c.When, however, the clutch-plate e is eccentric to the diskf, as shown inthe drawings, those cluches which are at a greater distance from thecenter of the spindle b are moving more rapidly than those clutcheswhich are nearer the spindle b, the result being that one or more of theclutches farther from the spindle b are in actionanddriving theclutch-plate c and those cl utchcs which are nearer to the spindle areslipping or doing no work, and according to the amount of eccentricitybetween the disk f and clutch-plate e the speed between these two partswill vary.

In Fig. 3 I have shown one method of regulating the relation of theplate 01 and the slide (Z The screwed rod h is provided at its upper endwith a hand-wheel h and atits lower end with a disk if, working betweena pair of jaws d forming part of the fixed plate d. The rod h is guidedat its upper part by a socket 77, carried by the top tube h4 of themachine. The screwed portion of the rod 7L works through ascrew-threaded collar d forming part of the slide 0F, and as the rod his rotated by its hand-wheel 7L so the slide 01 is raised or lowered,and consequently the clutch-plate e and diskfare placed more or lesseccentric with each other.

It is obvious that other methods of rotating the rod h may be employed.In Fig. 9 the screwed rod 7?. is provided at its upper end with aflanged drum h around which passes a cord or chain 71 guided by pulleys77. The ends of the chain or cord 71 may pass up to the handle-bar andbe operated by any suitable form of mechanism, as will be wellunderstood.

terior of the clutches and the rollers or balls 9 are forced outwardagainst the walls of the groove 6; but in Fig. 8 the oppositely-inclinedsurfaces g are shown facing one another and forcing the rollers or balls9 against a central flange or ring e Sucha form of clutch is found togive very good results, as there is so little surface in contact betweenthe clutches and the driven part. At the same time the grip is verypowerful and acts immediatelythat is to say, there is no back lashbetween the parts.

In a machine provided with the gearing herein described it is notnecessary to provide the rearchain-wheel with a free wheel-clutch, asthe clutch-plate e and its chain-teeth will overrun the clutches 9 whenthe cranks o are held stationary.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. In variable gearing for bicycles and the like, the combination of acrank-bracket, a spindle, cranks carried by the spindle, apart rotatingwith the cranks and spindle, a fixed plate carried by the crank-bracket,a bearing movably mounted with relation to the fixed plate, means foroperating said movablymounted bearing, a clutch-plate rotating on saidmovably-mounted bearing, a clutch-path on said clutch-plate, separateblocks working in connection with said clutch-path, oppositely-arrangedinclines in said blocks, balls acting between the inclines andclutch-path, and rods connected at one end to the frictionclutches andat the other end to the rotating part, substantially as set forth.

-2. In variable gearing for bicycles and'the The clutches shown are eachformed with like, the combination of a fixed bearing, a spindle rotatingin said bearing, cranks carried by the spindle, a part rotating with thecranks and spindle, a fixed plate carried by the frame of the machine, aslide moving in said fixed plate, means for actuating the slide, abearing carried by said slide, a clutch-plate rotating on said bearing,separate blocks working in connection with said clutch-plate,oppositely-arranged inclines in said blocks, balls acting between theinclines and the clutch-plate, and means for connecting the separateclutches with said rotating part, substantially as set forth.

3. In variable gearing for bicycles and the like, the combination of aspindle, cranks carried by the spindle, a part rotating withclutch-plate, and rods for connecting the clutches with said rotatingpart, substantially as set forth. at. In variable gearing for bicyclesand the like, the combination of a spindle, means for driving thespindle, a part .rotating with the spindle, a fixed plate carried by theframe of the machine, a slide moving in said fixed plate, means foractuating the slide, a hearing carried by said slide, a clutch-platerotating on said bearing, a clutch-path on said clutch-plate, separatesegment-shaped blocks working in connection with said clutch-path,oppositely-arranged inclines in the inner and outer curved faces of saidblocks, balls acting between the inclines and clutch-path, and rodsconnected at one end to the segmental friction-clutches and at the otherend to the rotating part, substantially as set forth.

5. In variable gearing for bicycles and the like, the combination of afixed bearing, a spindle rotating in said bearing, means for driving thespindle, a part rotating with the spindle, a fixed plate carried by theframe of the machine, a slide movingin said fixed plate,

means for actuating the slide, a bearing carried by said slide, aclutch-plate rotating on said bearing, separate segmental blocks workingin connection with said clutch-plate, oppositely arranged inclines insaid blocks, balls acting between the inclines and the clutch-plate, andmeans for connecting the separate clutches with said rotating part,substantially as set forth.

6. In variable gearing for bicycles and the like, the combination of afixed plate, a slide moving in said fixed plate, a bearing carried bythe slide, means for moving said slide, a clutch-plate rotating on saidbearing, chainteeth carried by said clutch-plate, a clutchpath. on saidclutch-plate, segmental blocks working in connection with said'clutch-path, I In testimonywhereof I affix my signature oppositelyainclined surfaces in the curved in presence of two Witnesses: faces' ofsaid blocks, balls acting between the inclined surfaces and the clutchpath, and MITCHELL means fol-connecting the clutches with apartWitnesses: I roteted by the cranks, substantially as set BFJMILLS,

- V CLAUDE K." MILLS.

forth.

